1. Field of the Invention
The present invention relates to seed meters for metering individual seeds at a controlled rate into a seed furrow, and more particularly to an arrangement for dislodging and removing seeds, seed particles, dirt and other debris which may become stuck or accumulate within apertures in a rotatable seed disk in a seed meter.
2. History of the Prior Art
Seed meters of various designs have been employed to dispense seeds at a controlled rate into a seed furrow as the seed meter is advanced along the furrow. In a typical arrangement a tractor is coupled to tow a tool bar to which are attached in generally parallel, spaced-apart relation a plurality of planting units with seed meter arrangements attached thereto. Each of the planting units includes a seed hopper for containing a quantity of the seed to be planted, a device for opening a furrow as the tractor drawn tool bar is advanced over the ground, a seed meter coupled to the seed hopper for metering or dispensing individual seeds into the furrow at a controlled rate and a further device for moving soil at the sides of the furrow to close the furrow over the seeds. The planting unit may further include containers for insecticide and fertilizer together with apparatus for dispensing controlled amounts of each.
Some seed meters are of the mechanical type in which mechanically actuated fingers or similar mechanical devices are typically used to separate individual seeds from a seed mass and then dispense them into a furrow. Other seed meters which are of the air type use an air pressure differential to pick up and then discharge individual seeds from a seed mass in controlled fashion. Typically, a rotating seed disk having one or more circumferential rows of apertures therein is used to pick up and then discharge the individual seeds.
Air seed meters may be of the positive pressure type in which air is blown into a seed chamber and onto the surface of the rotating seed disk or other movable member to create a higher than atmospheric pressure in the chamber. This forces seeds from a seed mass onto the seed disk where they are retained in the apertures for later release. The seeds are held against the apertures by the blowing air until they are released by interrupting the flow of air to the seeds. Examples of such air seed meters are provided by U.S. Pat. No. 3,888,387 of Deckler, No. 4,047,638 of Harrer and No. 4,074,830 of Adams.
Air seed meters may also be of the vacuum type in which a vacuum source is typically coupled to a separate chamber on the opposite side of the seed disk from the seed mass. The vacuum communicates through apertures in the seed disk to the seed mass to hold the seeds in place against the apertures as they are picked up from the seed mass and moved to the seed discharge area. An example of a vacuum seed meter is provided by U.S. Pat. No. 3,608,787 of Grataloup.
A further example of a vacuum seed meter which has particular advantages over seed meters of the prior art is provided by a co-pending application of William R. Lundie et al, Ser. No. 546,834, filed Oct. 31, 1983 and commonly assigned with the present application. The Lundie et al application describes a vacuum seed meter in which a seed disk is rotatably mounted within a housing so as to divide the interior of the housing into a first chamber adjacent a first side of the seed disk and an opposite second chamber at the opposite or second side of the seed disk. The seed disk is provided with one or more circumferential rows of apertures which extend through the thickness of the seed disk from the second side of the disk and terminate at the bottoms of recesses in the first side of the disk which define seed cells. The seed cells act to agitate, accelerate and then capture therein individual seeds from a seed mass within the first chamber. The individual seeds are held within the seed cells by a vacuum source coupled to the second chamber as the seeds are transported from the seed mass to a separate seed discharge area within the first chamber. At the seed discharge area the vacuum source is cut off from the apertures in the seed disk, allowing the individual seeds to fall out of the seed cells and through a chute to the ground below. The vacuum seed meter is usable with various different types of seeds, simply by changing the seed disk. Different seed disks have different sized apertures and different sizes and configurations of the connecting seed cells depending on the particular seed or type of seed to be metered by the seed meter.
In seed meters of the type described in previously referred to co-pending application Ser. No. 546,834 of Lundie et al as well as in other types of seed meters employing a rotatable, apertured seed disk, it sometimes happens that one or more of the apertures become clogged with seeds, seed particles, dirt or other debris. Such problems may occur, for example, where a seed being carried by one of the apertures in the seed disk between the seed mass and the seed discharge area somehow becomes stuck in the aperture. While the aperture diameter is typically chosen to be considerably smaller than the average size of seeds that the disk is designed for use with, unusually small seeds of that type or more often broken seeds or seed particles may become lodged within the apertures. It also sometimes happens that dirt or other debris may build up within the apertures. Sometimes this happens quickly, while at other times it occurs gradually over a period of time. A partial or complete clogging of one or more of the seed disk apertures by a seed, seed particles, dirt or other debris typically results in the aperture which is so clogged being thereafter unable to pick up and discharge a seed therefrom. This is harmful at the very best, and may render use of the seed meter unacceptable for certain applications, particularly if very many of the apertures should become clogged and therefore inoperative.
Ideally, therefore, the seed disk apertures should be kept free of unwanted matter such as seed particles, dirt and other debris. This should be done frequently, and preferably with each revolution of the seed disk so that each aperture therein can be prepared following each release of a seed therefrom to once again pick up a seed from the seed mass and release it in the seed discharge area.
Accordingly, it would be desirable to provide an improved seed meter having an arrangement for removing debris from apertures in a rotating seed disk therein.
It would furthermore be desirable to provide a seed meter in which an arrangement is provided for dislodging or removing debris from the apertures in the seed disk virtually with each revolution of the seed disk.
It would still furthermore be desirable to provide a seed disk having an arrangement which is effective in removing debris from the apertures in different seed disks designed for use with different seed types or sizes within the same seed meter.